U.S. Pat. No. 6,364,780 proposes a process of assembling a driveshaft from a first attachable part, a second attachable part and a tube element. Each of the two attachable parts includes a cylindrical receiving face whose outer diameter is smaller than the inner diameter of the tube element. For connecting the three components, the attachable parts and the tube element are aligned independently of one another on a reference axis while partially overlapping, and are then welded to one another. It is assumed that straight tube elements are available. Any curvature of the tube element resulting from its production is not taken into account.
DE 35 10 091 C2 describes a driveshaft for motor vehicles, having a tube and two attachable elements. The attachable elements are provided in the form of universal joints which are inserted into the ends of the tube and connected thereto by welding. The attachable elements each comprise a portion with a reduced diameter which is introduced into the tube, as well as a shoulder which rests against the associated end of the tube in order, thus, to achieve accurate positioning. After the attachable element has been inserted into the tube, the two components are aligned relative to one another in a defined way.
From DE 35 09 306 A1 there is known a tube assembly, more particularly a driveshaft/joint head assembly as well as a method of producing same. The tube assembly comprises a driveshaft and a joint head coaxially welded on to same. The end of the driveshaft is thickened towards the joint head, with its inner circumference being toleranced in such a way that, in the assembled condition, a sliding fit is achieved between the driveshaft and the joint head. After the two components have been made to contact one another by means of their conical faces and thus have assumed a defined position relative to one another, they are welded to one another.